Traffic control system



March 5, 1946. j "J. BAUMFALK 2,395,798-

TRAFFIC CONTROL SYSTEM Filed Dec. 17,1942 ssheets-sneeti f 2 Q5 lNVENTORq, 'J. BAU MLK 'Ma'rch 5, 1946. J. BAUMFALK TRAFFIC CONTROL SYSTEM FiledDec. 17, 1942 5 Sheets-Sheet 2 INVENR'JR J BAUM/ZL/f ATTORNEY .1.BAUMFALK 2,395,798

TRAFFIC CONTROL SYSTEM March 5, 1946.

3 Sheets-Sheet 3 Filed Dec. 1'7, 1942 v U. R m 0 0 TM T MM M N V v 7 IIIa m L383 v 6 8558 J 33 8.3 V

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Patented Mar. 5, 1946 'Eelephone Laboratories, Incorporated, New

Yo'rk, N. Y.,a corporation of New Yorlr Application December 17, 1942,SerialNo. 469,299-

12 Claims.

This invention relates to telephone systems and has for its object thecontrol of telephone traflic loads in emergencies.

In thebaseof emergencies, such as attack by enemy forces, it is apparentthat it might be desirable to deny service to private subscribers.

in order that the central o-fficeequipment be adequate to handlemilitary and civilian defense traffic. For this purpose 'it has beensuggested that the telephone lines may be divided into several groups orclasses and manual keys provided by which service may be cut off fromthe diiferent classes of lines according to the requirements of theemergency.

.It is the object ofthe present invention to provide means to controlthe removalof classes oflines from service and the, restoration of themto service under centralized remote control.

To guard against unauthorized persons interfering with service, thiscentralized control means is responsive only to a series of, operationsnot likely to be performed accidentally and a code is employed whichdiffers from any used in service.

More specifically, means is provided for removing the classes of lines.from service responsive to a predetermined number of identical,successively dial-ed digits. and for restoring the lines to serviceresponsive to a similar operation but employing a difierent digit. r

In addition means is provided, responsive to the dialing of the samedigit a predetermined plurality of times, for obtaining an indication ofthe busy condition of the equipment used by subscribers in originatingconnections.

Means. is also provided for, ascertaining whether any group of lineshasbeen removed from service and which group or groups. 7

These and other features of the invention will be more clearlyunderstood from a consideration of the following description inconnection with the drawings in which;

Figs. 1 and 2 show the remote control equipment; and

Fig. 3 shows both the line load control equipment and the means forchecking the busy condition of the call originating switches.

When it becomes desirable to employ line load control in a particularoffice, a study will be made of the subscribers lines terminating inthat oflice for the purpose of dividing the lines into classes inaccordance with their importance in the case of an emergency. Lines suchas police station lines, fire station lines, hospital lines, etc., willall circumstances. The division oi the remaining lines into classes Band C will be on atrafno basis so that the removal ofv either-class willrelievethe traffic load in allpparts of they Qffioe.

The line load control circuit shown in detailiin Fig. 3. is thatbelonging to class C7,. while t'he'load control circuit for the class B-lines is indicated by the box 355). J

The subscribers line I 00 andthe connecting link iii! are to be taken;as illustrative only of any desirable means of connecting an. authorizedoflicial line with the remote control equip ment shown. This equipmentmay be seizedi'as indicated over a selector terminal bank or, may bereached through an; operatorsposition or over an interoiiice trunk inwhich case suitable terminating jacks would be provided. 7

When a connection has been established with the remote controlequipment, a circuit is completed from battery through the upper windingof relay I92 over the incoming connection to the calling dial and backto ground through the, lower winding of relay H12. Relay Hl2 inoperating closes an obvious circuit for relay Ill-3 which is slow torelease. Relay IE3 at contact 41 connects ground to the sleeve conductorI20 therebymarlring the circuit busy and holding the switches over whichthe connection was, extended to the remote control circuit. At contact2-, relay H13 completes a circuit over contact 8 of relay H2: to thewinding of relay H3 and battery. Relay 3 operates and looks over contact5 tov'ground at contact 3 of relay E03 independentof; relay H2. Relay II3 connects ground to conductors 121. I22 and 23 to. providelockingcircuits' to .beqdce scribed hereinafter. Ground on conductor P22also extends over; normal contact 2H of switch 2m to the winding ofrelay I04 and battery, -op-.- erating relay Hi4.

Switches 2m and 22B are rotary switches, s'witchZlll' including brush 2Hand off-normal contacts 215 to Zll. The switch. is. rotated by steppingmagnet 2M and restored to normal by release magnetv 2J3; Switch220includes. brushes 22! and 222, off-normal contacts 225; and 226;, isadvanced by stepping magnet 2-24. and is restored by release magnet 223.

When the authorized person or .ofiicial located at substation I00 nextoperates his dial, relay )2 falls. back, closing a circuit from groundover the back contact of relay I02, contact 6 of relay H3, lower contactof relay 10.4, contact 3 of relay E05, winding of magnet 2M to :battery.The first step of switch 2H1 opens contact 2|! and closes input in classA and will receive service under contacts M5 and H6. Contact 2|! opensthe previously traced circuit for relay I04 but relay I04 is slow torelease and before relay I04 can open its contacts, contact 2 I6 closesa circuit for relay I04 in parallel with magnet 2I4. Because of itsslow-to-release character, relay I04 remains operated between the pulseswhich operate magnet 2I4 to advance switch 2 I0.

In order to render the remote control equipment efiective, apredetermined digit, for example, the digit 2 must be dialed a pluralityof times. At the end of the first digit, brush 2II will rest on contact252 and they circuit of relay I04 will be opened long enough to permitthat relay to release. When relay I04 closes its upper contact, acircuit is completed from ground over contact I of relay I03, uppercontact of relay I04, contact I of relay I06, brush 2, terminal 252,contact I of relay 2I8 to the winding of relay 232 and battery. Relay232 looks over contact 2 to ground on conductor I2I. Relay 232 alsocloses a, circuit from battery through winding of relay I06, contact Iof relay I01, contact equipment in the ofiice. Relay I08 operates inparallel with relay 244, the circuit extending as above traced fromground to contact 4 of relay I09 and thence over contact I of relay I05to the winding of relay I08 and battery. Relay I03 looks over contact I,to ground on conductor I23.

Referring to Fig. 3, substation 3I0 represents any one of thesubscribers lines in the ofilce at which the remote control equipment islocated. When a call is originated on line 3I0, line relay 3I2 isoperated. Relay 3I2 connects battery through resistance 3I3 in parallelwith battery through cut-01f relay 3 to the sleeve contact 3 of relay232, contact 9 of relay 2I8, to ground on conductor I2I. Relay I06operates and closes a holding circuit for itself over contact I of relayI01, contact 2 of relay M6, back contact of relay I04, contact I ofrelay I03 "to ground. At contact 3, relay I06 closes a circuit fromground through the winding of relay 2E8, to battery. Relay 2I8 operatesand looks over its contacts 8 to grounded conductor I 2| Relay 2 I8opens the original operating circuit for relay I06, closes a circuitfrom ground on its contacts I6, contact 4 of relay I06, oil-normalcontacts 2I5 to the winding of releasemagnet 2I3 and battery, therebyrestoring switch 2I0 to normal, opening contacts 2I5 and 2I6, andreclosing contact 2I1.

The dial is now reoperated to again transmit the digit 2. Relay I02responds to the dial pulses as before and again operates relay I04 whichin turn opens the holding circuit of relay I06, permitting that relay torelease. Brush 2I I is advanced into contact with terminal 252 in themanner previously described. At the end of the digit, relay I02 remainsoperated, relay I04 releases and the circuit previously traced to thebrush 2 is closed. However, since relay 2I8 is now operated, the circuitextends over terminal 252, contact I4 of relay 2I8, contact 5 of relay232, to the winding of relay I01 and battery. Relay I01 operates andlocks over its contact 3, back contact of relay I04 to ground at contactI of relay I03. At contact 2 relay I01 closes an obvious circuit forrelay I06 which now operates. At contact 4 relay I01 closes acircuit forrotary magnet 224 of switch 220 advancing the switch one step to closecontacts, 225 and 226. Since relay 2I8 is still operated, the operationof relay I 06 closes the previously traced circuit for release magnet2I3 and switch 2 I0 is restored to normal.

When the dial is operated to transmit the next digit 2, the holdingcircuit for relay I 01-is opened and that relay releases in turnreleasing relay I06 and magnet 224.

Following each dialing of the digit 2, relay I01 is operated and switch220 advanced one step. When the switch 220 has advanced a predeterminednumber of steps, for example, six steps, brush 222 engages terminal 221and a circult is closed from ground at contact 1 of relai 2I8, brush222, terminal 221, contact 4 of relay I09, contact I of relay 232 to thewinding of relay 244 and battery. Relay 244 controls switch 200 to testthe condition of the cell o ig at g individual to the line in thevarious line finders which have access to the line, to mark the line ascalling. In addition, line relay 3I2 connects ground to the winding ofgroup relay 303. Relay 303 is common to the group of lines includingline 3I0 and operates in response to the initiation of a call on anyline of this group. When operated, relay 303 connects ground to thestart circuit of a group of line finders of which line finder 304 isone. The line finder 304 operates to find the calling line and, when theline is found, cut-oil relay 3 is operated and locked to the sleeveconductor under the control of the line finder circuit. The operation ofcut-off relay 3 releases line relay 3| 2, in turn releasing group relay303 unless some other line in the group is also calling. I

As each finder of the group of finders is taken for use it extends thestart circuit to the next finder and subsequent calls in the group oflines including line ,3I0 or in any other group to which these findershave access will be served by line finders in the group including linefinder 304 in rotation. Each finder of the group, when idle, connectsbattery to the winding of relay 302 so that relay 302 remains operatedas long as there is one idle line finder in the group. When the lastfinder has been taken for use, relay 302 releases operating relay 30Iwhich thereupon connects ground to conductor 330 lighting lamp 300.Conductor 330 is also connected to a terminal of switch 200.

When it is decided to provide emergency load control in an office theback contact of a relay, such as relay 3I5, is inserted in the circuitsof all group relays such as relay 303 for class B and C lines. Thefunction of relay-3I5 will be discussed hereinafter. It is to beunderstood that the arrangement is equally applicable to officesemploying other types of ,line findersor to those employing lineswitches. In the latter case the contacts of the relay like relay 3I5will be inserted in the battery supply circuit of the line switches. Theline finders serving lines in class A will not be altered. Line finder304 is assumed to be of the type disclosed in Patent 1,799,654 to R. LStokely, April 7, 1931.

, With relay 244 operated, a circuit is closed from tone source 240,which may be the source of dial tone, over contact I of relay 24I,contact I of relay 242, contact 1 of relay 244, contact 4 of relay I05to the tip conductor of the incoming circuit, thereby transmitting apreliminary or warning tone to the substation I00 indicating that thecircuit is ready to test the condition of the line finder groups. Relay244 also closes a circuit from ground at its contact 9, contact 3 ofrelay 243 to the winding of relay 245 and battery.

A circuit is also closed from battery through the winding of relay 246,contact 5 of relay 244 to brushes 20I and 202 of switch 200. Directground is connected to the first six terminals of the arc served bybrush 202 and, therefore, in the first six positions of brush 202, thecircuit of relay 24B is completed to ground and relay 240 operates. Withrelays 245 and 24B operated, a circuit is closed from battery throughthe winding of relay 243, contact 5 ofrelay 245, front contact of relay245, contact of relay .244 to ground. Relay 243 operates in thiscircuit, opening the circuit of relay 245 which releases slowly, in turnopening the circuit of relay 243, which likewise releases slowly. Duringthe time that relays 243 and. 245 are operated, a circuit is closed frombattery through the winding of stepping magnet 201, contact 2 of relay245, contact 2 of relay 243 to ground at contact 9 of relay'244. Switch200 is, therefore, advanced over its first six positions under thecontrol of relays 243 and 245.

When brush 200 reaches position 5, a circuit is closed from ground overbrush 206 in position 5 to the winding of relay 242 and battery.Relay'242 locks over its contact 2, contact 2 of relay 244, to groundover brush 204'. At contact I, relay 242 opens the tone circuit toterminate the preliminary tone.

When'switch 200 reaches position I, the circuit of relay 246 is open andrelay 246 releases and closes a circuit from battery through the windingof relay 208, contact 4' of relay 244, back contact of stepping magnet201, back'contact of relay 246 to ground at contact 8 of relay 244.Relay 208 operates slowly in this circuit and, when operated, closes acircuit from battery through the winding of magnet 20?, front contact ofrelay' 208, back contact of relay 246 to ground-at contact 8 of relay244. Magnet 20? ance operates, opening the circuit of relay 208 whichreleases, in turn opening the magnet circuit. Magnet 20'! releases,stepping switch 200 to position 8. While switch 200 was in position 'I,a circuit was closed from ground over brush 206 v in position I to thewinding of relay 24I andbattery. Relay 24! operates, looks over itscontact 3 to ground in parallel with relay 242 and prepares a new tonecircuit.

Conductor 330, individual to the group of lines containing line 3H1 asindicated in Fig. 3, is connected to the terminal of brush 202 inposition 5. If this group of line finders still contains one or moreidle finders, no ground will be connected to conductor 33!! and switch200 will be advanced to position 9 under the control of relay 208 asdescribed for the advance to position8. Assuming, however, that theentire group of line finders is busy, so that ground is connected toconductor 330, a circuit will beclosedfrom round on conductor 330 overbrush 202, contact 5 of relay 244 through the winding of relay 240 tobattery. Relay 246 operates, opening the circuit of relay 208 andclosing a circuit from ground, at contact 8- of relay 244, front contactof relay 246, contact 3 of relay 245 to the winding of relay 243 andbattery. As described in the advance of switch 200 to position 5, relays243 and 245 close a circuit for stepping magnet 20? which steps switch200 to position-0.

and the functions above described will be repeated as long as the remotecontrol circuit is held. At any time after the ofiicial hears-the prelim'inary tone signal, he may disconnect, thereby re leasing relay I02followed by relays I03, H3, I08, H8, 232, 244, 24!, 242 and 245. Sincerelay I03 is slow to release, relay I02 in releasing closes a circuitfrom ground at its back contact, over contact 6 of relay II3, contact 5of relay 244 Winding of relay H2 to battery through resist- II4. RelayII2 operates in this circuit and locks over its contact 4 to ground atcontact 2 of relay I00, and contact 5 of relay I09. The operatingcircuit of relay I I2 is opened when relay H3 releases. ,Relay H2, inoperating, closes a circuit from ground over contact 5 of relay II I,contact 5 of relay II2, off-normal contact 225 of switch 220 to batterythrough the winding of release magnet 223 thereby restoring switch 22 0to normal.

Relay H2, in operating, starts the measurement of a time interval withinwhich the re mote control equipment remains in readiness :for

further operation. To this end, relay II2 closes a circuit from groundover interrupter I24, contact l of relay II2, contact 5 of relay I03,winding of relay H0 and battery. Relay III] operates at each closure ofthe interrupter contact. At the first closure of the front contact ofrelay H0, anobvious circuit is closed for relay III which looks over itscontact 2 to ground at contact 3'of relay H2. When the interrupter I24opens its contact, relay H0 releases closing a circuit from ground overits back contact, contact I of relay III, contact 2 of relay H2 tothewinding of stepping magnet 224 of switch 220.

Switch 220- is therefore stepped under the concircuit to be selected,for example, 30 seconds.

When brush 22! reaches terminal 228 a circuit is closed from ground overcontact 3 of relay III, brush 22I, terminal 228 to battery throughresistance H4 in shunt of the winding of relay II2,-causing relay II2 torelease. Relay H2 at contact 3 opens one locking circuit for relay IIIbut relay III remains operated to ground over oil-normal contact 220.With relay II 2- released,

a circuit is closed from ground at contact 4 of.

relay Ill. contact 0 of relay H2, off-normal contact 225, winding ofrelease m'agnet'223 to 7 244, to ground over brush-1203 or brush204.

The speed'of interrupter I24 and a that he previously dialed the digit2. 'The digits used for particular functions have been selectedarbitrarily, but others mightoe employed by changing the connections ofrelays 232 to 231 at the contacts of relay 218. The reselection of theremote control circuit operates relays 1112 and 103. Since relay 112 isheld operated, relay 1 13 cannot operate, but a circuit is closed from'ground over contact 2 of relay 1113, contact 1 of relay 112, contact 8of-relay 113 to battery through the winding of relay 1119.- Relay 1B9operates in this circuit and looks over its contact 1, contact f relay232 to ground at con tact 3 of relay 133. 'When relay 139 operates, it'opens the locking circuit for relay 112 and that relay releases. Withrelay 112 released, relay 113 is permitted to reoperate. 109 operated,relays 234 to 231 are rendered effective. Prior to the operation ofrelay 133 only relays 232 and 233 are effective.

Assuming that it is desired to remove from service the class 0 lineswhich include line 3111;

the official will dial the digit 5 at least seven times; Switch 210 isadvanced in the manner previously described until it reaches position 5.When relay 1112 remains operated and relay 1114 released following thefirst digit, the circuit previously traced is completed from ground atthe contact of relay 123 to brush;2l1 and over the fifth contact ofbrush 211, contact 5 of relay 218 to the winding of relay 235 andbattery. Relay 235 operates and looks over its contact 2 to ground onconductor 121. With relay 235 operated, relay 106 is operated, thecircuit extending over contact 3 of relay 235 insteadof over con- Withrelay tact 3 of relay 232. Relay 133 operates, in turn operating relay218 and restoringswitch 210 to normal. When brush 211 is advanced toposition 5 in response to the second digit, relay 101 is operated, inturn operating relay 1136 and stepping switch 221]. When switch 228 hasbeen advanced to position 1, a circuit is closed from ground at contact1 of relay 218,brush 222, terminal 221, contact 3 of relay11l9, contact'1 of relay 235 to the winding of relay 321 in the load call by any linein'class C.

In addition, relay 315 closes a circuit from ground through lamp 314,resistance 318, winding of relay 311fto battery, lighting the lamp toindicate which class of line has been removed from service. Relay 311operates in this circuit and closes an obvious circuit for relay 323.Relay 323 at its contact 4 lights lamp 331 and at contacts 1 and 2closes a circuit for operating buzzer 325 to inform the localmaintenance man that a portion of the lines has beenremoved fromservice. In addition, relay 323 closes a circuit from battery throughthe windingof relay 319,

aaea'zes right contact of relay 321, contact 5 of relay 323, normalcontact of key 328 to ground at the back contact of relay 1 11 in theremote control circuit. Relay 31s operates in-this circuit locking overits'contact 3 and contact 5 of relay 323 to ground at the contact ofrelay 111, independent of relay 321. At its contact 2 relay 319 closes alocking circuit for relay 315 thereby locking the class C lines out ofservice after the remote control circuit has been released. At contact4, relay 319 closes a circuit for relay 115 in the remote controlcircuit. With relay 113 operated a circuit is closed from the code 2ringing source over conduo-tor 129, contact 4 of relay I16, contact 4 ofrelay 235, condenser 241, contact 4 of relay 105 to the tip conductor ofthe incoming circuit to inform the official that the classC lines havebeen removed from service. r

The ofiicial now disconnects. He may permit the remote control circuitto restore to normal as previously described; he may reseize the remotecontrol circuit and again dial a series of 2s to detemine the efiect ofthe removal of the class C lines in relieving the congestion, or he maydial a series of 4s to remove the class B lines from service. Theoperation in either case is substantially as above described. Dialing aseries of 4s results in the operation of relay 234 and relay 234causes'the operation of, a relay similar to relay 321 in the class Bline load control circuit351l, which in turn opens the line finder grouprelay circuits for the class B lines and brings about the operation ofrelay 118. Relay 118 closes a tone circuit from the code 1 ringingsource to indicate that the class B load control circuit has functioned.Dialing a series of 2s results in the operation of relay 232 aspreviously described. Relay 232 in operating opens the locking circuitof relay 109 and that relay releases to reclose the operating circuit ofrelay 244. I

When the emergency is over and it is desired to restore the class B andclass C lines to service, the ofiicial will again seize the remotecontrol circuit and dial a series of 2s in order to condition thecircuit. He will then disconnect and re- 7 will dial a series of 6s oraseries of '1s in order to restore the class B or class C linesrespectively.

Dialinga series of 7s will cause the operation of relay 231 at the endof the first digit. When the series has been completed, a circuit isclosed from ground at contact 1 of relay 218, brush 222, terminal 221,contact 3 of relay 1B9, contact 1 of relay 231 to the winding of relay 111 and battery. Relay 1 11 operates in this circuit and opens thelocking circuit for relay 319 permitting that relay to release and inturn release relay 315 and the other similar relays associated with theclass C lines.

Dialing a series of its results in the operation of relays 236 and 113to restore the class B lines to service.

If the ofiicial wishes to determine whether any lines have been removedfrom service and which relay 233 operated, the advance of switch 221] inresponse to the subsequent digits places brush 222 in engagement withterminal 221, completing a circuit from ground over contact] of relay2I8, brush ZZZ-{terminal 22-1, contact I of relay 233, winding of relayH and battery. Assuming that only the classG lines have been removedfrom service, relay H6 will be operated alone and the operation of relayH5 will close a tone circuit from the tip conductor of the incomingconnection, contact 4 of relay I05, condenser 241, contact 4 or relay233, contact'4 of relay H5, contact 2 of relay I I6, contact 3 of relayH8 to conductor I29 and the code: 2 ringing source. Therefore, theoflicial will hear the 2-ringcode and will be informed that the .class-C lines are out of service.

If only theclass B lines have been removed from service so that onlyrelay H8 has been onerated, the tonecircuit extends as above traced tocontact 4 of relayl I5 and thence over contact 3 of relay H6 and contact2 of relay IIB to conductor I28, and the code I ringing generator. If nolines have been removed from service, the tone circuit extends fromcontact 4 of relay H5 over contact 3 of relay H6, contact I of relay H8,contact 5 of relay H5, to conductor I21 which extends to a source ofsteady ringing current.

Whenever relay H5 is operated, a circuit is closed from battery throughthe winding'of relay I25 over contact I of relay H5 to conductor I23, towhich ground is connected at the rate of sixty impulses per minute. Ifboth class B and class C lines have been removed from service, the tonecircuit extendsfrom contact 4 of, relay H5,

-contact 2 of relay I I0, contact 4 of relay I I8,- over the frontcontact ofrelay I25 to conductor I21.

Therefore, steady ringing current, interrupted at a rate of sixtyinterruptions perminute, is connected to the tone circuit as anindication that both the class B and class C lines have been removedfrom service.

The operation of relay I I5 also serves to silence the alarm in the lineload control circuit. Assuming that the class C lines have been removedfrom service so that relay HIS is operated, relay I I 5 in operatingcloses a-circuit from ground over contact 2 of relay H5, contact I ofrelay H6, upper normal contact of key 328, upper winding of relay 324 tobattery Relay 324 operates in this circuit and looks over contactsor key328, front contact of relay 324 to ground at contact 3 of relay 323. Atits lower contact, relay 324 opens the circuit of buzzer 325. A similararrangement is provided for silencing the alarm associated with theclass B load control circuit 350.

To guard against the accidental selection and operation of theloadcontrol circuit, the remote control circuit is so arranged that'if,after operating one of the relays 232 to 231, a difierentdigit isdialed, no circuitis completed for relay I01 since the circuit of thatrelay extends over the contact or the operated relay to the terminal ofbrush 2I I over which the relay was originally'op Grated. Furthermore;if such a digit is dialed, when relay I04 releases, a circuit i's'closedfor relay I05. Assuming, for example, that relay 232 had been operatedand that subsequently the digit 3 was dialed, when relay I04 releasesfollowing the dialing of the digit 3, a circuit-will be closed fromground, contact I of relay I03, back contact of relay I04, contact I ofrelay'I05', brush 2H in position 3, contact I2 of relay 2I8,'contact Iiof relay 233, to the winding of relay I05 and battery. Relay I05 at itscontact 2 closes an obvious circuit for relay I08 which looks under thecontrol of relay I I3. At contact 3 relay I05 opens the operatingcircuit for stepping magnet 2I4, preventing the operation ofswitch 2I-0in re sponse to subsequent digits and atcontact 4 opens the tonecircuit. Relay I05 releases when the official disconnects, releasingrelays I02 and I03 to'restore the remote con trol circuit to normal.

It is also possible to remove the lines of class C from service underlocal manual control by momentarily operating key 321, thereby closing acircuit for relay 32I which functions as previously described, ,Thelines may also be restored to service manually by momentarily operatingkey BIG thereby releasing'relay 1H5.v A separate key, like key SIB, isprovided for each relay 315 so thateach relay must be released:separately. When all of the relays 3I5 havebeen released, relay 3IIreleases,'in turn releasing the remainder of the load control relays.

If it should be desirable to remove lines within a class of lines fromservice, thismay' be accomplished by operating key 328. Key 320 at itsout-- or lower alternate contacts connectsrrelay 3I9 to ground at theback contact of relay H1, and; at its inner lower alternate'contactsconnects relay 323130 a local ground. Relays 319 and 323 operate. If nowrelay 3I5- isoperated by hand, relay 3I5 will lock-to ground at contact2 of relay, 3I9 and remain operated. The buzzer may be silenced byoperating key 326 which connects ground over the upper alternatecontacts of key 328 to the lower winding of relay 324 and battery,operating relay 3-24.- i

I-f relay 3I5 is operated falsely and lamp 3I4 is burned? out so thatnoalarmis sounded, relay I 3 I 9 will not be operated-and relay 3 I 5-closes a cirsuit from battery through itslower winding and lowercontact, over key 3I3, contact I of relay M9 to ground through thewinding of relay 320. Relay 3I5 will not lock in this circuit but relay320 operates, connecting ground to the winding of relay 323, operatingrelay 323 to sound an alarm.

With relay 244-operated, it the oflicialattempts to dial an additionaldigit, a circuit will be closed, when relay I02 falls back in responseto the first interruption of the extra digit from ground over the backcontact of relay I02, contact 6 of relay H3, contact 0 of relay 244tothe winding of relay H2, resistance H4 and battery. Relay I I2 looksover its contact 4 to ground at contact 2 of relay I-08.- With relay H2looked, a circuit is closed from battery through the windingof. magnet2I4 of switch 2I0,- contact 30f relay I05, iront contact of; relay I04,-contact 6- of relay. 244,- contact 4- of relay H2 to ground at contact'Zof relay I08, thereby closing a steady circuit for magnet 2I4 throughoutthe digitand preventing its response to the dial pulses. If any extradigits are dialed after the remote control circuit has been released andreseized, relay I09 is operated and, when relay I08- operates inparallel with either relay II'I, relay H9 or relay 32I, the circuit forholding magnet 2l4 operated: will extend as previously traced to thefront contact of relay I04 and thence over contact 20f relay I09,contact 3' of relay I08, contact-4- of relay" I I2 to ground-at contact2 of relay I 08- rendering the remote control circuit independent ofexcess digits.

What is claimed is:

1.In a telephonesystem; subscribers lines divided into groups, switchingequipment, aline relay for each of said lines, meansr'esponsive to the'operation ofthe lirierelay of anyone "of said lines for connecting saidline with said switching equipment, meansfor disabling the responsivemeans pertaining to all of the lines in certain of said groups of lines,a directively operable switch, and means including said switch foroperating said disabling means- .7 a r i 2. In a telephone system,subscribers lines divided into groups, switching equipment, a line relayfor each of said lines, means responsive to the operation of the linerelay of any one of said lines for connecting said, line :with saidswitching equipment, means for. disconnecting said responsive means fromall of the lines in certain of said groups of lines, adirectivelyoperable switch, and means including said switch foroperating said disconnecting means.

3. In a telephone system, subscribers lines divided into groups,switching equipment, means responsive to the initiation of a call on anyone of said lines for connecting said line with said switchingequipment, and means for directively disabling the responsive meanspertaining to certain of said groups of lines comprising registeringmeans,-means for repeatedly positioning said registering means inresponse to the dialing of the same digit, and means responsive to apredetermined number of reoperations of said registering means tooperate said disabling means.

4. In a telephone systemfsubscribers' lines divided into groups,switching equipment, means responsive to the initiation of a call on anyone of said lines for connecting said line with said switchingequipment, means for directively disabling the responsive meanspertaining to certain of said groups of lines comprising registeringmeans, means for repeatedly positioning said registering meansin'response to the dialing of the same digit, means responsive to apredetermined number of reoperations of said registering means to"operate said disabling means, and means to prevent the operation ofsaid disabling means if said registering means is reoperated inrespo'nse to a difierent digit. 5. In a telephone system, subscriberslines divided into groups, switching equipment, means responsive to theinitiation of a'call on any one of said lines for connecting said linewith said switching equipment, means for directively disabling theresponsive means pertaining to oer-'- tain or saidgroups of linescomprising register ing 'means'means forrepeatedly positioning saidregistering means in response to the dialing-of the same digit, meansresponsive :to a predetermined number iof reoperations ofsaid'registering means to operate said disabling means, and meansoperated in accordance with the value of said digit to determine" thegroups of lines'for which the responsive means shall be disabled.

6. In a telephone system, subscribers linesdivided into groups switchingequipment, means responsive to the initiation of a call on anyone ofsaid lines for-connecting said line with said switching equipment, means'for directively disabling the responsive means pertaining to certain ofsaid groups of lines comprising registering means, means for'repeatedlypositioning said registering means in response to the same digit, meansresponsive to a predetermined number of reoperations of said registeringmeans to operate said disabling means, and means responsive V to apredetermined number of operations of 'said registering. means inresponse. to a different digit forreleasing said disabling means. 7. Ina telephone system,'subscrihers. lines divided-into groups. switchingequipment, means responsive tothe initiation of a call on'any one ofsaid lines for connecting said line with said registering means in'oneof said groups of lines.

switching equipment, means for directively disabling the responsivemeans pertaining to certain of said groups of lines comprisingregistering means, means'for repeatedly positioning said registeringmeans in response to the same digit, means responsive to' apredetermined number of reoperations of said registering means tooperate said disabling means, means responsive to a predeterminednumber. of operations of said registering means in response'to' adifferent digit for releasing said'disabling means, and means operatedin accordance with the value of said other digit to determine the groupsof. lines for which the responsive means shall be reenabled.

8. In a telephone system, subscribers. lines divided into groups,switching equipment,.connecting means responsive to .the initiation of acall on any one of said lines. for connecting said lines with saidswitching equipment, said connecting. means also divided into groups,indicating means operated when each one of said groups of connectingmeans becomes busy, means for determining which of said groups ofconnecting means are'busy comprising means for successively connectingwith "the indicating means of each of said groups of, connecting means,and means responsive to connection with an operated indicating means forgenerating a pulse of tone.

9. In a telephone system, subscribers lines divided into groups,switching equipment, connecting means responsiveto the initiation of acall on any one of said lines for connecting said lines with saidswitching equipment, said ,connecting means also divided into groups,indicating means operated when each one of said groups of connectingmeans becomes busy, means for determining which of said groups ofconnecting means are busy comprising registering means, means forrepeatedly positioning said registering means in response to the samedigit, means responsive to a predetermined number of reoperations ofsaid registering means for successively connecting with thefindicatingmeans oiF-each of said groups of connecting means, and means responsiveto connection with an operated indicating means for generating a pulseof tone.

10. In a telephone system, subscribers" lines divided into groups,switching equipment, connecting. means responsive to the initiation of acall on any one of'said linesforuconnecting said lines with saidswitching equipment, said connectingmeans also divided into groups,indicating means operated when each one of'said groups of connectingmeans becomes busy, means for determining which of said groups ofconnecting means are busy comprising a'control circuit, means forselecting said ,control' circuit, said control circuit, means forrepeatedly positioning said registering means in response to-the samepredetermined digit, means responsive to a predetermined number ofreoperations of said registering means for successively connecting withthe indicating means of each. ofsaid groups .of; connecting means, meansresponsive to' connectionwith an operated indicating means forgenerating a pulse of tone, means responsive tothe, release of. said.control circuit for rendering said registering means responsive toother digits, and means responsive to the reselection ofsaid, controlcircuit and the registration of oneof. said'other digits to disable saidconnecting means a'ssociated'with 11. In a telephone system, subscriberslines divided into groups, switching equipment, connecting meansresponsive to the initiation of a call on any one of said lines forconnecting said lines with said switching equipment, said connectingmeans also divided into groups, indicating means operated when each oneof said groups of connecting means becomes busy, means for determiningwhich of said groups of connectin means are busy comprising a controlcircuit, means for selecting said control circuit, registering means insaid control circuit, means for repeatedly positioning said registeringmeans in response to the same predetermined digit, means responsive to apredetermined number of reoperations of said registering means forsuccessively connecting with the indicating means of each of said groupsof connecting means, means responsive to connection with an operatedindicating means for generating a pulse of tone,

means responsive to the release of said control circuit for starting atiming operation, and means responsive to the reselection of saidcontrol circuit prior to the termination of said timing operation andthe repeated registration of another digit to disable said connectingmeans associated with one of said group of lines.

12. In a telephone system, subscribers" lines divided into groups,switching equipment, connecting means responsive to the initiation of acall on any one of said lines for connecting said lines with saidswitchng equipment, saidconnecting means also divided into groups,indicating means operated when each one of said groups of connectingmeans becomes busy, means for determining which of said groups ofconnecting means are busy comprising a control circuit, means forselecting said control circuit, registering means in said controlcircuit, means for repeatedly positioning said registering means inresponse to the same predetermined digit, means responsive to apredetermined number of reoperations of said registering means forsuccessively connecting with the indicating means of each of said groupsof connecting means, means responsive to connection with an operatedindicating means for generating a pulse of tone, means responsive to therelease of said control circuit for starting a timing operation, andmeans effective if said control circuit is reselected prior to thetermination of said timing operation to selectively disable theconnecting means associated with a particular group of lines or toreenable said connectingmeans in accordance with the digit registered.

JOHN BAUMFALK.

